dataflavor.java

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            throw new NullPointerException("mimeType");
        }
	try {
            initialize(mimeType, humanPresentableName, classLoader);
        } catch (MimeTypeParseException mtpe) {
            throw new IllegalArgumentException("failed to parse:" + mimeType);
        }
    }       
    
    /**
     * Constructs a <code>DataFlavor</code> from a <code>mimeType</code> string.
     * The string can specify a "class=<fully specified Java class name>"
     * parameter to create a <code>DataFlavor</code> with the desired 
     * representation class. If the string does not contain "class=" parameter,
     * <code>java.io.InputStream</code> is used as default.
     * 
     * @param mimeType the string used to identify the MIME type for this flavor;
     *                 if the class specified by "class=" parameter is not
     *                 successfully loaded, then an
     *		       <code>ClassNotFoundException</code> is thrown
     * @exception ClassNotFoundException if the class is not loaded
     * @exception IllegalArgumentException if <code>mimeType</code> is
     *	               invalid
     * @exception NullPointerException if <code>mimeType</code> is null
     */
    public DataFlavor(String mimeType) throws ClassNotFoundException {
        super();
        if (mimeType == null) {
            throw new NullPointerException("mimeType");
        }
        try {
            initialize(mimeType, null, this.getClass().getClassLoader());
        } catch (MimeTypeParseException mtpe) {
            throw new IllegalArgumentException("failed to parse:" + mimeType);
        }
    }

   /**
    * Common initialization code called from various constructors.
    *
    * @param mimeType the MIME Content Type (must have a class= param)
    * @param humanPresentableName the human Presentable Name or 
    *                 <code>null</code>
    * @param classLoader the fallback class loader to resolve against
    *
    * @throws MimeTypeParseException
    * @throws ClassNotFoundException
    * @throws  NullPointerException if <code>mimeType</code> is null
    *
    * @see tryToLoadClass
    */
    private void initialize(String mimeType, String humanPresentableName, ClassLoader classLoader) throws MimeTypeParseException, ClassNotFoundException {
        if (mimeType == null) {
            throw new NullPointerException("mimeType");
        }
        
        this.mimeType = new MimeType(mimeType); // throws
	
	String rcn = getParameter("class");
	
	if (rcn == null) {
            if ("application/x-java-serialized-object".equals(this.mimeType.getBaseType()))
		    
                throw new IllegalArgumentException("no representation class specified for:" + mimeType);
            else
                representationClass = java.io.InputStream.class; // default
        } else { // got a class name
            representationClass = DataFlavor.tryToLoadClass(rcn, classLoader);
        }
        
        this.mimeType.setParameter("class", representationClass.getName());
        
        if (humanPresentableName == null) {
            humanPresentableName = this.mimeType.getParameter("humanPresentableName");
            if (humanPresentableName == null) 
                humanPresentableName = this.mimeType.getPrimaryType() + "/" + this.mimeType.getSubType();
        }
        
        this.humanPresentableName = humanPresentableName; // set it.
        
        this.mimeType.removeParameter("humanPresentableName"); // just in case
    }

    /**
     * String representation of this <code>DataFlavor</code> and its
     * parameters. The resulting <code>String</code> contains the name of
     * the <code>DataFlavor</code> class, this flavor's MIME type, and its
     * representation class. If this flavor has a primary MIME type of "text",
     * supports the charset parameter, and has an encoded representation, the
     * flavor's charset is also included. See <code>selectBestTextFlavor</code>
     * for a list of text flavors which support the charset parameter.
     *
     * @return  string representation of this <code>DataFlavor</code>
     * @see #selectBestTextFlavor
     */
    public String toString() {
        String string = getClass().getName();
        string += "["+paramString()+"]";
        return string;
    }
    
    private String paramString() {
        String params = "";
        params += "mimetype=";
        if (mimeType == null) {
            params += "null";
        } else {
            params += mimeType.getBaseType();
        }
        params += ";representationclass=";
        if (representationClass == null) {
           params += "null";
        } else {
           params += representationClass.getName();
        }
        if (DataTransferer.isFlavorCharsetTextType(this) &&
            (isRepresentationClassInputStream() ||
             isRepresentationClassByteBuffer() ||
             DataTransferer.byteArrayClass.equals(representationClass)))
        {
            params += ";charset=" + DataTransferer.getTextCharset(this);
        }
        return params;
    }

    /**
     * Returns a <code>DataFlavor</code> representing plain text with Unicode
     * encoding, where:
     * <pre>
     *     representationClass = java.io.InputStream
     *     mimeType            = "text/plain;
     *                            charset=&lt;platform default Unicode encoding&gt;"
     * </pre>
     * Sun's implementation for Microsoft Windows use the encoding <code>utf-16le</code>.
     * Sun's implementation for Solaris and Linux use the encoding
     * <code>iso-10646-ucs-2</code>.
     *
     * @return a <code>DataFlavor</code> representing plain text
     *    with Unicode encoding
     */
    public static final DataFlavor getTextPlainUnicodeFlavor() {
	String encoding = null;
	DataTransferer transferer = DataTransferer.getInstance();
	if (transferer != null) {
	    encoding = transferer.getDefaultUnicodeEncoding();
	}
	return new DataFlavor(
	    "text/plain;charset="+encoding
	    +";class=java.io.InputStream", "Plain Text"); 
    }

    /**
     * Selects the best text <code>DataFlavor</code> from an array of <code>
     * DataFlavor</code>s. Only <code>DataFlavor.stringFlavor</code>, and
     * equivalent flavors, and flavors that have a primary MIME type of "text",
     * are considered for selection.
     * <p>
     * Flavors are first sorted by their MIME types in the following order:
     * <ul>
     * <li>"text/sgml"
     * <li>"text/xml"
     * <li>"text/html"
     * <li>"text/rtf"
     * <li>"text/enriched"
     * <li>"text/richtext"
     * <li>"text/uri-list"
     * <li>"text/tab-separated-values"
     * <li>"text/t140"
     * <li>"text/rfc822-headers"
     * <li>"text/parityfec"
     * <li>"text/directory"
     * <li>"text/css"
     * <li>"text/calendar"
     * <li>"application/x-java-serialized-object"
     * <li>"text/plain"
     * <li>"text/&lt;other&gt;"
     * </ul>
     * <p>For example, "text/sgml" will be selected over
     * "text/html", and <code>DataFlavor.stringFlavor</code> will be chosen
     * over <code>DataFlavor.plainTextFlavor</code>.
     * <p>
     * If two or more flavors share the best MIME type in the array, then that
     * MIME type will be checked to see if it supports the charset parameter.
     * <p>
     * The following MIME types support, or are treated as though they support,
     * the charset parameter:
     * <ul>
     * <li>"text/sgml"
     * <li>"text/xml"
     * <li>"text/html"
     * <li>"text/enriched"
     * <li>"text/richtext"
     * <li>"text/uri-list"
     * <li>"text/directory"
     * <li>"text/css"
     * <li>"text/calendar"
     * <li>"application/x-java-serialized-object"
     * <li>"text/plain"
     * </ul>
     * The following MIME types do not support, or are treated as though they
     * do not support, the charset parameter:
     * <ul>
     * <li>"text/rtf"
     * <li>"text/tab-separated-values"
     * <li>"text/t140"
     * <li>"text/rfc822-headers"
     * <li>"text/parityfec"
     * </ul>
     * For "text/&lt;other&gt;" MIME types, the first time the JRE needs to
     * determine whether the MIME type supports the charset parameter, it will
     * check whether the parameter is explicitly listed in an arbitrarily
     * chosen <code>DataFlavor</code> which uses that MIME type. If so, the JRE
     * will assume from that point on that the MIME type supports the charset
     * parameter and will not check again. If the parameter is not explicitly
     * listed, the JRE will assume from that point on that the MIME type does
     * not support the charset parameter and will not check again. Because
     * this check is performed on an arbitrarily chosen
     * <code>DataFlavor</code>, developers must ensure that all
     * <code>DataFlavor</code>s with a "text/&lt;other&gt;" MIME type specify
     * the charset parameter if it is supported by that MIME type. Developers
     * should never rely on the JRE to substitute the platform's default
     * charset for a "text/&lt;other&gt;" DataFlavor. Failure to adhere to this
     * restriction will lead to undefined behavior.
     * <p>
     * If the best MIME type in the array does not support the charset
     * parameter, the flavors which share that MIME type will then be sorted by
     * their representation classes in the following order:
     * <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>,
     * <code>[B</code>, &lt;all others&gt;.
     * <p>
     * If two or more flavors share the best representation class, or if no
     * flavor has one of the three specified representations, then one of those
     * flavors will be chosen non-deterministically.
     * <p>
     * If the best MIME type in the array does support the charset parameter,
     * the flavors which share that MIME type will then be sorted by their
     * representation classes in the following order:
     * <code>java.io.Reader</code>, <code>java.lang.String</code>,
     * <code>java.nio.CharBuffer</code>, <code>[C</code>, &lt;all others&gt;.
     * <p>
     * If two or more flavors share the best representation class, and that
     * representation is one of the four explicitly listed, then one of those
     * flavors will be chosen non-deterministically. If, however, no flavor has
     * one of the four specified representations, the flavors will then be
     * sorted by their charsets. Unicode charsets, such as "UTF-16", "UTF-8",
     * "UTF-16BE", "UTF-16LE", and their aliases, are considered best. After
     * them, the platform default charset and its aliases are selected.
     * "US-ASCII" and its aliases are worst. All other charsets are chosen in
     * alphabetical order, but only charsets supported by this implementation
     * of the Java platform will be considered.
     * <p>
     * If two or more flavors share the best charset, the flavors will then
     * again be sorted by their representation classes in the following order:
     * <code>java.io.InputStream</code>, <code>java.nio.ByteBuffer</code>,
     * <code>[B</code>, &lt;all others&gt;.
     * <p>
     * If two or more flavors share the best representation class, or if no
     * flavor has one of the three specified representations, then one of those
     * flavors will be chosen non-deterministically.
     *
     * @param availableFlavors an array of available <code>DataFlavor</code>s
     * @return the best (highest fidelity) flavor according to the rules
     *         specified above, or <code>null</code>,
     *         if <code>availableFlavors</code> is <code>null</code>,
     *         has zero length, or contains no text flavors
     * @since 1.3
     */
    public static final DataFlavor selectBestTextFlavor(
                                       DataFlavor[] availableFlavors) {
        if (availableFlavors == null || availableFlavors.length == 0) {
            return null;
        }

        if (textFlavorComparator == null) {
            textFlavorComparator = new TextFlavorComparator();
        }

        DataFlavor bestFlavor = 
            (DataFlavor)Collections.max(Arrays.asList(availableFlavors), 
                                        textFlavorComparator);

        if (!bestFlavor.isFlavorTextType()) {
            return null;
        }
        
        return bestFlavor;
    }

    private static Comparator textFlavorComparator;

    static class TextFlavorComparator 
        extends DataTransferer.DataFlavorComparator {

        /**
         * Compares two <code>DataFlavor</code> objects. Returns a negative
	 * integer, zero, or a positive integer as the first
	 * <code>DataFlavor</code> is worse than, equal to, or better than the
	 * second.
         * <p>
         * <code>DataFlavor</code>s are ordered according to the rules outlined
	 * for <code>selectBestTextFlavor</code>.
	 *
         * @param obj1 the first <code>DataFlavor</code> to be compared
         * @param obj2 the second <code>DataFlavor</code> to be compared
         * @return a negative integer, zero, or a positive integer as the first
         *         argument is worse, equal to, or better than the second
         * @throws ClassCastException if either of the arguments is not an
         *         instance of <code>DataFlavor</code>
         * @throws NullPointerException if either of the arguments is 
         *         <code>null</code>
	 *
	 * @see #selectBestTextFlavor
         */
        public int compare(Object obj1, Object obj2) {
            DataFlavor flavor1 = (DataFlavor)obj1;
            DataFlavor flavor2 = (DataFlavor)obj2;

            if (flavor1.isFlavorTextType()) {
                if (flavor2.isFlavorTextType()) {
                    return super.compare(obj1, obj2);
                } else {
                    return 1;
                }
            } else if (flavor2.isFlavorTextType()) {
                return -1;
            } else {
                return 0;
            }
        }
    }

    /**
     * Gets a Reader for a text flavor, decoded, if necessary, for the expected